Dyeing proteinaceous and nylon materials



r 2,90,218 lce Patented Aug. 18, 1959 DYEING PROTEINACEOUS AND NYLOMATERIALS No Drawing. Application February 7, 1956 Serial No. 563,839

20 Claims. (Cl. 8-54) This invention relates to compositions and methodsfor dyeing proteinaceous and nylon materials and more particularly tocompositions and methods utilizing high affinity wool dyes.

The high affinity wool dyes, which are sometimes referred to as millingcolors or neutral dyeing acid dyes, have several advantages and inparticular have the advantage that they generally result in colors whichare reasonably fast to washing. Unfortunately dyes of this class havethe severe disadvantage that they are not level dyeing colors and theuse of such dyes frequently results in objectionable area or fibershading. Numerous efforts have been made in the past to develop leveldyeing procedures utilizing the milling colors. For example, it issuggested in U.S. Patent 2,590,847 that an ammonium salt be added to thedye bath so that as the salt decomposes, the pH of the dye bath isgradually lowered and the dye is slowly and uniformly exhausted onto thetextile material. This procedure is undoubtedly an improvement over theprior art practice of adjusting the pH by acid additions but it is nowapparent that pH control is not the complete solution to the problem ofobtaining level shades with milling colors. It has also been suggested(Journal Society of Dyers and Colourists, page 297, volume 64, 1948)that dyeings with milling colors might be started at the boil instead ofstarting the dyeing at a low temperature and gradually raising thetemperature of dye bath to the boil in a conventional manner. The highinitial temperatures in this suggested process apparently decrease thedye particle size and increase fiber swelling and this should beconducive to level dyeing. While the procedure undoubtedly has somemerit, it is difficult to practice and fails to give satisfactoryresults in a large number of instances.

phobic substituents It has now been found according to this inventionthat even under exceedingly adverse conditions, level shades can beobtained with milling colors by adding to the dye bath a compoundselected from the group consisting of bases represented by the formula:

wherein R R and R represent members selected from the group consistingof hydrogen, monocyclic aromatic radicals, aliphatic radicals, andcycloalkyl radicals, and R represents a radical selected from the groupconsisting of monocyclic aromatic, aliphatic and cyoloalkyl radicals;and acid addition salts thereof.

The nature of the members R to R inclusive may vary within reasonablywide limits although strongly hydroare preferred and best results areusually obtained when the total effect of the four groups is such as toreduce the solubility of the free base to such a value that it is notcompletely soluble in the dye bath at the concentration employed.Typical substituent groups which may be represented by R to R includephenyl, tolyl, cyclohexyl, benzyl, and aliphatic hydrocarbon radicalshaving from 1 to 25 carbon atoms as illustrated by butyl, dodecyl,stearyl and allyl radicals. Illustrations of specific compounds whichmay be employed are sym.-diphenylguanidine, sym.-o-ditolylguanidine,u,a, -tetramethylguanidine, a,a-diphenylguanidine, cit-phenylguanidine,sym.-dibenzylguanidine, a-cyclohexylguanidine, and a-dodecylguanidine.Sym.diphenylguanidine is the presently preferred reagent primarilybecause it is readily available and low in cost.

The process of this invention is useful in any instance Whereunlevelness is or may be encountered when employing the high afiinity ormilling dyes on proteinaceous or nylon materials. Frequently moredifliculty is encountered when employing a given milling dyestuff on onetype of fiber than when employing the same dyestuff on other fibers,and, for example, dyestuffs which give a reasonably level shade uponwool by conventional expedients give an extreme degree of unlevelnessupon chlorinated woolens. Not only will the chlorinated wool be dyedmore heavily near the tips of the fibers but area shading will beapparent throughout the dyed fabric. Likewise, uneven dyeing isfrequently a greater problem with nylon rugs or the like than with plainweave fabrics. The process of this invention will alleviate tippy dyeingand/ or area shading even with chlorinated woolens and nylon pilefabrics and makes an even shade more readily obtainable in any instancewhere a milling color is employed.

The milling colors do not constitute a precise class of dyes but aregenerally considered to be a part of the class of dyestuffs known asacid dyes. They differ from the more conventional acid dyes in that theyresult in a greater degree of fastness to milling or alkaline scouringand also differ in that they exhaust from the dye bath at a higher pH.Generally the higher the pH at which the dye will exhaust, the greaterthe degree of wash fastness and the greater the tendency of the dye togive uneven shading. There is no sharp dividing line between the millingcolors and conventional acid dyes, but since any dyestufi which gives asatisfactory degree of exhaustion at or above a pH of about 5 displays ameasure of fastmess to milling and generally gives difficulties withshading, it is intended that milling colors be defined, for the purposesof this specification, to include all such dyes. It is also intendedthat milling colors include certain direct. dyes for cottons which canbe used as neutral dyeing colors for W001 or the like, and certainneutral dyeing colors which are best used with a mordant. The followingis a representative list of dyestuffs with which the invention will befound to be useful: Milling Yellow HSGA (PR. 138) Polar Yellow 2G Cone.(Cl. 642), Cloth Fast Yellow RS (PR- 187), Irgalan Brown 2GL (Geigy),Xylene Milling Red G (Cl. 443), Nylanthrene Scarlet YLFW (AlthouseChemical Company), Erie Scarlet B (Cl. 382), Crocein Scarlet N EX. (C1.252), Anthraquinone Violet D (C1. 1080), Erio Anthracene Cyanine ZRL(Geigy), Pontacyl Fast Blue SB 150% (C1. 209), Suprarnine Pure Blue BL(General Dyestulf Corporation), Carbolan Brilliant Blue 2R Cone.(Arnold, Hoffman), Brilliant lndocyanine 6B A (PR. 222), GenalanBrilliant Blue BCF (General Dyestuff Corporation), Supernylite Blue BR(Althouse Chemical Company), Alizarine Cyanine Green G EX. (Q1. 1078)Pontachrome Fast Grey L (PR. 206). Many of the above dyes represent oneof a general class made by a given manufacturer and in such instancesthe invention is useful with the entire class.

The amount of the dyestuff employed may be conventional and depends uponthe color and shade desired. For very light shades it is frequentlynecessary to employ only a small fraction of one percent, based on theweight of goods, of dyestuif and frequently dyeings are I conductedemploying 0.02% or less dyestuff. On the other hand, an excellent blackcan generally be obtained employing only about 6% dyestuff so that thereis seldom any advantage in using a greater quantity of dye, although ininfrequent instances the amount of dyestuff employed may be as high as10% or based on the weight of goods to be dyed.

The amount of the guanidine type compound employed may be varied withinwide limits. For example, satisfactory results can sometimes be achievedwhen employing as much as 10 to 15% of the guanidine compound based uponthe weight of material to be dyed, but the use of such large amounts iswasteful and in some instances adversely aifects the hand of the dyedfabric. Generally there is no advantage in using more than about 4% ofthe guanidine compound on the weight of the material to be dyed and thepreferred upper limit is 2% on the weight of the goods. Much smalleramounts can frequently be employed and in some instances it has beenobserved that unlevelness can be eliminated by employing as little as0.1%, based on the the weight of goods, of the guanidine compound.Generally, however, when dyeing other than very light shades, it isadvantageous to employ .at least about 0.25% of the guanidine compoundon the weight of the goods since any reasonable excess over the minimumamount required does not adversely affect the efliciency of the dyeingnor the hand of the dyed fabric.

The guanidine compound is preferably insoluble in a basic dye bath inthe concentrations employed so that it is usually necessary to employthe same in the form of a dispersion. The dispersion can be formed inany manner and the only requirement is that the dispersion be reasonablystable during the dyeing operation. For example, the guanidine compoundin the form of its acid addition salt may be dissolved in a small amountof water, preferably containing a suitable dispersing agent, and thesolution can thereafter be neutralized with sodium hydroxide or otherbase to result in precipitation of the free guanidine base in the formof finely dispersed particles. Alternatively one can employ a colloidalmill or the like for producing a concentrated dispersion which canthereafter be added to the dye bath. The preferred method for formingthe dispersion, however, comprises dissolving the free guanidine base ina large quantity of a suitable dispersing agent and thereafter addingthis solution to the dye bath. Any anionic or nonionic dispersing agentcapable of acting as a solvent for the guanidine base may be employedfor this purpose, and the following are only illustrative examples:highly sulfonated castor oil, sodium l-iso-butyl-4-ethyloctyl sulfate,monop-nonylphenyl ether of hexaethylene glycol, sodium monop-octylphenylether of diethylene glycol sulfate. The preferred dispersing agent whenemploying such a pro cedure comprises sulfonated castor oil since thisdispersing agent has a leveling effect upon milling colors in itself andsupplements the leveling action of the guanidine compound. The guanidinecompounds are, however, not sufficiently soluble in sulfonated castoroil to permit, in some instances, the use of this dispersing agentalone. Such a large amount of the castor oil derivative would berequired that it might affect the hand of the goods, and, for thisreason, it is generally advantageous to employ approximately equal partsof sulfonated castor oil and a second compound in which the guanidinecompounds has a greater solubility, such as an alkylarylpolyethersulfate dispersing agent. It is also generally advantageous to employthe minimum amount of the dispersing agent mixture in which theguanidine compound is soluble or, in other words, about 4 to 12 parts ofdispersing agent for each part of the guanidine compound. A satisfactoryprocedure comprises mixing together the two dispersing agents, addingthe guanidine compound, warming the mixture until the guanidine compoundis competely dissolved and thereafter adding the solution to the dyebath with agitation.

The improvement of this invention can be incorporated into anyconventional dyeing procedure with the milling colors including the highinitial temperature procedure discussed above. The preferred procedure,however, comprises dispersing the guanidine compound in a dye bath equalin weight to from about 10 to 60 times and preferably from 20 to 40times the weight of the goods to be dyed, adjusting the temperature ofthe bath, adding the goods, and after about 5 or more minutes to allowthe goods to be thoroughly wet by the bath, adding the dyestuff. Thetemperature of the bath at the time the goods and dyestulf are enteredmay vary from room temperature to the boiling point of the bath or evenhigher if pressure equipment is employed, but since a low temperatureassists in reducing the initial dye strike or, in other words, theamount of the dye that is exhausted onto the fabric in the first fewminutes of dyeing, and since a high temperature according to thisinvention is not required to break up the dye agglomerates, a low temperature for entering the goods and the dyestuif into the bath isgenerally advantageous. On the other hand, a suitable dispersion of theguanidine compound can, as a general rule, be more readily made if thedye bath is slightly warmed before the guanidine is added; With regardto both of these considerations, the dye bath may advantageously be at atemperature of from about 70 to 150 F. and is preferably at atemperature of from about to F. at the time the goods are enteredtherein and the dyestuff, is added.

While the temperature of the bath has some afiect upon the initial dyestrike, the initial pH of the dyebath is the most important factorinfluencing this variable and is also important for other reasons. Ifthe initial pH of the dye bath is too low, the initial dye strike willbe so great that an unlevel dyeing might result, and if the pH of thedye bath is too high, damage to goods may result.

' As a general rule the pH should be high enough so that not more than40% and preferably not more than 20% of the dyestuff exhausts upon thefabric during the first 10 minutes of the dyeing cycle and while theexact pH required for this result will vary depending upon thetemperature of the bath, the particular color or colors employed and thetype of goods being dyed, as a general rule an initial dye bath pH of atleast about 7 will give satisfactory results. An initial dye bath pH of10 or higher may be employed with nylons but the initial pH should notbe above about pH 8 with wool containing materials since above thisvalue there is danger that the wool might be damaged. In many instances,the pH of the dye bath as prepared is such that pH adjustment is notrequired, but if such is found to be necessary, the pH of the bath canreadily be brought to a proper value by the addition of a small quantityof acid, base or buffer salt.

When the goods and dyestulf are added to the dye bath with the latter ata relatively low temperature, it is generally necessary to thereafterincrease the temperature of haustion. The rate at which the temperatureof the dye bath is increased can vary from an exceedingly low value, asillustrated by 01 F. per minute, up to the limits of the apparatusemployed or in other words up to about F. per minute. Conventional ratesof temperature increase give excellent results and as a general rule arate of temperature rise of from about 2 to 5 F. per minute ispreferred. Raising the temperature of the bath can be commencedimmediately after adding the dyestufi, if desired, although analternative procedure which is advantageous in some instances comprisesretaining the dye bath at a constant temperature for from about 5 to 10minutes to allow completion of the initial dye strike.

The ultimate temperature of the bath may be conventional and mostmilling colors are conventionally dyed at the boil. If, however, thereis danger of damage to the fabric or if a low terminal temperature isadvantageous for other reasons, reasonably satisfactory results cangenerally be achieved byemploying a terminal tem perature of only about180 F. Likewise, one can employ pressure equipment and raise thetemperature of the both above the boiling point, although such aprocedure is seldom, if ever advantageous.

As the dyeing progresses, it is generally advantageous to graduallyreduce the pH of the dye bath to thereby hasten the exhaustion of thedye and to result in a more complete exhaustion of the dye onto thefabric or the like. This invention results in the dye bath pH being lesscritical than in prior art procedures using the milling colors but, forbest results, the pH of the bath should be reduced onto the fabric. Many'lling colors will exhaust to a reasonably complete degree at a pH of 6or higher and in some instances the terminal pH may be as high as 7.5.On the other hand, some milling colors require a terminal pH of about 5for a satisfactory degree of exhaustion. The terminal pH of the dye bathis not extremely critical as long as the degree of exhaustion issatisfactory and good results can generally be achieved utilizing aterminal pH of 5 even with a dye that completely exhausts at a pH of 6so that, if desired, one can simply reduce the pH of the bath to about 5regardless of the dyestuif em ployed.

The length of time required for reasonably complete exhaustion of thedye bath is determined primarily by the rate at which the pH of the bathis reduced. As a general rule, the slower the rate of exhaustion, themore level the dyeing but a very level color can generally be obtainedby controlling the rate of exhaustion such that the bath is at itsterminal temperature for from about as evenly and uniformly as possibleand sudden changes in pH should be avoided. For-this reason, the use ofan ammonium or other heat decomposable salt is generally advantageous asit permits an exceedingly uniform reduction in the pH of the bath, andeliminates the sudden pH changes which are inherent in the alternativeprocedure of adding small quantities of dilute acid asthe dyeingprogresses. In some instances it is advantageous to resort to the use ofa decomposable salt in combination with acid additions and this isparticularly true when one desires a terminal pH which is slightly lowerthan can be readily achieved with ammonium salts. By such a combinationof reagents the pH of the bath can be controlled during the early partof the dye cycle by the ammonium salt, and near the termination of thedyeing, the pH can be lowered by dilute acid additions to achieve a morenearly complete exhaustion of the dye. The amount of acid forming saltand/ or free acid that is added to the dye bath is determined entirelyby the necessary requirements for reducing the pH of the bath to asuitable terminal value and this amount will "vary depending upon theamount of dyestuff, guanidine compound and other reagents employed inthe dye bath as well as the terminal pH necessary for a reasonablycomplete exhaustion of the dyestuif. From about 2 to 5%, based on theweight of goods, of the acid forming salt is generally suificient toresult in a satisfactory terminal pH without resorting to acid additionsand it is seldom advantageous to use more than about 10 to 15% of thesalt. If too little is employed and the exhaustion of the dye bath isnot reasonably complete, it is usually possible to add a small amount ofacid to drop the pH to a suitable terminal value. Examples of suitableacid producing salts which may be employed in the process are ammoniumacetate, ammonium sulfate and diammonium phosphate. Examples of suitableacids which may be employed include acetic acid and propionic acid.Inorganic acids such as hydrochloric or sulfuric acid can be employedbut are generally not advantageous because of the small changes in pHwhich are desired.

Themost advantageous terminal pH for the dye bath depends entirely uponthe nature of the dye employed and the terminal pH is preferably thatwhich will just result in a reasonably complete exhaustion of the dye 30minutes to one hour. If one is employing an acid liberating salt, therate of exhaustion can be controlled by varying the amount of the saltused and by the selection of a salt having the particularcharacteristics desired. If the pH is being partially or totallycontrolled by acid additions, the rate of exhaustion can be controlledby the frequency of addition and the quantity of acid added.

The invention will now be illustrated by the following specific examplesin which all parts are by weight unless otherwise indicated:

Example I Into a dye beck there is loaded pounds of a chlorinated woolenmaterial containing'12V2% nylon, and approximately 950 gallons of waterat a temperature of about 80 F. There is then slowly added to the beck0.55 pound of sym.-diphenylguanidine dissolved in 2.75 pounds ofsulfonated castor oil (Monipol Oil 48) and 1.1 pounds of analkylarylpolyether sulfate dispersing agent sold under the trade name ofTriton 770. Diphenylguanidine is only slightly soluble in water and theaddition of the dispersing agent solution results in a line dispersionof the guanidine compound in the bath. The pH of the bath at this timeis approximately 7.6. After about 10 minutes and with the dye bath stillat a temperature of about 80 F., there is added 0.092 pound of BrilliantIndocyanine GA-CF (PR. 223) dissolved in about 4 gallons of water. Thetemperature of the dye bath is then slowly raised to the boil over aperiod of one hour and the pH at the boil is found to beapproximaltely7.85. After 40 minutes at the boil the steam is cut and 0.55 pound ofacetic acid are added very slowly. The dye 'bath is then retained at theboil for an additional 20 minutes at the end of which time the degree ofexhaustion is satisfactory. The pH of the dye bath at this time is about5.2. The dye bath is dropped, and the goods rinsed and dried. Thefinished goods have an excellent hand and are found to have been dyed avery level and bright aqua blue.

Example II Into a dye beck there is loaded pounds of a woolen fabric andapproximately 1,000 gallons of water at a temperature of approximately75 F. There is then added to the bath approximately 4.2 pounds ofammonium acetate and 0.56 pound of sym.-diphenylguanidine dissolved in3.5v pounds of sulfonated castor oil and 1.4 pounds of analkylarylpolyglycol non-ionic dispersing agent sold under the trade nameof Tergitol NPX. The pH of the bath at this time is approximately 7.5.After approximately 10' minutes there is added to the batha dye mixturecomprising 3.85 pounds of Polar Brown 2GL (Geigy Chemical Corporation),0.14 pound of Erie Scarlet B (C1382) and 0.112 pound of AlizarineCyanine Green G (C1 1078) and the temperature of the dye bath isthereafter raised to the boil over a period of approximately one hour.After approximately 45 minutes at the boil the degree of exhaustion issatisfactory and the pH is found to be approximately 6.0. The dye bathis dropped and the goods are rinsed and dried. The finished goods arefound to have an excellent hand and are dyed a level brown color.

Example III Into suitable dyeing apparatus there is loaded 80 parts byweight of a woolen fabric and 3,200 parts by weight of water at atemperature of approximately 80 F. There is then added to the bath 2parts by weight of diammonium phosphate and 0.4 part by weight of sym.-tet'ramethylguanidine dissolved in 2.5 parts of a sodium alkyl sulfatewetting agent sold under the trade name of Tergitol Anionic 4. After aperiod of approximately 15 minutes with the dye bath still at atemperature of about 80 F., there is added a dye mixture comprising0.335 part of Benzyl Fast Orange G (Ciba), 0.48 part of Benzyl FastYellow G (Ciba) and 2.0 parts of Erio Fast Cyanine Green G (C1 1078).The dye bath is raised to the boil over a period of approximately 45minutes and retained at the boil for approximately one hour after whichthe bath is dropped and the goods rinsed. The finished goods have anexcellent hand and are dyed a level green.

Example IV Into a suitable dye apparatus there is loaded 90 parts byweight of a woolen fabric and approximately 350 parts by weight of waterat a temperature of about 80 F. There is then added to the bath 2.7parts of ammonium sulfate and 0.25 part of sym-dibenzylguanidinedissolved in 2.3 parts of sulfonated castor oil and one part of analkylarylpolyether sulfate wetting agent sold under the trade name ofTriton 770. After a period of about minutes there is added a dye mixturecomprising 0.135 part of Alizarine Cyanine Green G (CI 1078), 1.12 partsof Polar Brilliant Violet BL (Geigy) and 0.18 part of AnthraquinoneViolet D (CI 1080). The temperature of the dye bath is then raised tothe boil over a period of about 50 minutes and after about 30 minutes atthe boil there is slowly added 0.4 part of acetic acid. The dye bath isretainedat the boil for an additional minutes and then dropped. Thefinished goods have an excellent hand and are dyed a level lavendarshade.

The procedure for employing other guanidine compounds and otherdyestuffs is the same as illustrated in the above examples.

Having thus described my invention what I desire to claim and secure byLetters Patent is:

1. In a process for dyeing with high aflinity milling colors textilefibers selected from the group consisting of nylon and proteinaceousfibers, the improvement which comprises adding to the bath in which thefibers are dyed a guanidine compound selected from the group consistingof bases represented by the formula:

wherein R R and R represent members selected from the group consistingof hydrogen, monocyclic aromatic radicals, aliphatic radicals, andcycloalkyl radicals, and R represents a radical selected from the groupconsisting of monocyclic aromatic, aliphatic and cycloalkyl radicals;and acid addition salts thereof.

2. The improvement of claim 1 wherein the guanidine compound issym.-diphenylguanidine.

3. The improvement of claim 1 wherein the guanidine compound is employedin amounts of from about 0.1% to 15% based upon the weight of goods tobe dyed.

4. The improvement of claim 1 wherein the guanidine compound is added tothe dye bath in the form of solution in an organic solvent comprising adispersing agent.

5 The improvement of claim 4 wherein the dispersing agent comprisessulfonated castor oil.

6. A process for dyeing with high afiinity milling colors textile fibersselected from the group consisting of nylon and proteinaceous fibers,which process comprises placing the goods to be dyed in an aqueous bath,dispersing in said bath, prior to the addition of dyestuff, a guanidinecompound selected from the group consisting of bases represented by theformula:

wherein R R and R represent members selected from the group consistingof hydrogen, monocyclic aromatic radicals, aliphatic radicals, andcycloalkyl radicals, and R represents a radical selected from the groupconsisting of monocyclic aromatic, aliphatic and cycloalkyl radicals;and acid addition salts thereof, adjusting the pH of the bath to a valueof at least about 7 but not sufficiently high to result in damage to thegoods, adding a dyestuif solution containing at least one milling dyeand thereafter heating the dye bath to result in the dye being exhaustedonto said goods.

7. A process according to claim 6 wherein the guanidine compound anddyestuif are added at a temperature below about F. and the dyebath isthereafter heated to a temperature of at least about F.

8. A process according to claim 7 wherein the pH of the bath is reducedduring the dyeing to a terminal value of no more than about 6.

9. A process according to claim 8 wherein the pH is reduced by theprocedure which comprises adding to the dye bath an ammonium salt whichdecomposes under the influence of heat to liberate an acid.

10. A process according to claim 9 wherein the ammonium salt is ammoniumacetate.

11. A process according to claim 8 wherein the guanidine compound isadded to the dyebath in the form of a solution in a dispersing agent.

12. A process according to claim 11 wherein the dispersing agentcomprises sulfonated castor oil.

13. A process according to claim 6 wherein the guanidine compound is adiarylguanidine base.

14. A process according to claim 13 wherein said guanidine base issym.-diphenylguanidine.

15. A process according to claim 6 wherein the guanidine compound. is adiaralkylguanidine base.

16. A process according to claim 15 wherein the guanidine base issym.-dibenzylguanidine.

17. A process according to claim 6 wherein the guanidine compound is analkylguanidine.

18. A process according to claim 17 wherein the guanidine base issym.-tetramethylguanidine.

19. A process for dyeing proteinaceous materials with high affinitymilling colors which process comprises placing the material to be dyedin an aqueous bath, dispersing in said bath a guanidine compoundselected from the group consisting of bases represented by the formula:

wherein R R and R represent members selected from the group consistingof hydrogen, monocyclic aromatic radicals, aliphatic radicals, andcycloalkyl radicals, and R represents a radical selected from the groupconsisting of monocyclic aromatic, aliphatic and cycloalkyl radicals;and acid addition salts thereof, adjusting the pH of said bath to avalue of from about 7 to 8, adding the milling color dyestufi while thetemperature of the bath is not higher than about 110 F., raising thetemperature of the bath to at least about 180 F. and gradually reducingthe 10 pH of the bath to a value of from about 5 to 6.

20. A process according to claim 19 wherein the material to be dyed is achlorinated woolen fabric and the guanidine compound issym.-diphenylguanidine.

References Cited in the file of this patent UNITED STATES PATENTS2,448,448 MacGregor Aug. 31, 1948 FOREIGN PATENTS 547,844 Great BritainSept. 14, 1942

